Unit 3 – Lecture 9

PhotosynthesisPhotosynthesis: the process used by

autotrophs which changes solar energy, water [H2O], and carbon dioxide [CO2] into glucose [C6H12O6] and oxygen [O2]

Equation for Photosynthesis: E + H2O +CO2 C6H12O6 + O2

Photosynthesis – cont’dtakes place in the chloroplasts of the cell

“chloro” – green [pale green]contain green pigment,

chlorophyll“phyll / phyllos” = leafchloroplasts are

FILLED with chloroPHYLL

Light Dependent Reactionssunlight

transfers a photon of solar energy to

chlorophyll in the chloroplast

which exites an electron

e- gets knocked out of placement

Light Dependent Rxns – cont’de- travels down the Electron

Transport Chain [ETC][also called Electron Transport System - ETS]

as e- travels, it loses E

that E splits H2O [called photolysis]

into …

Light Dependent Rxns – cont’dthat E splits H2O [called photolysis] into

Oxygen [O2] Gas and Hydrogen [H+] Ions

which is released into the atmosphere

Light Dependent Rxns – cont’d… Hydrogen [H+] Ions…

which either

bonds with NADP+

to form NADPH

which goes to the light independent reactions

Light Dependent Rxns – cont’d… Hydrogen [H+] Ions…

which either

is pumped into the thylakoid

to form a gradient

of charge AND

concentration [called electrochemical

gradient]

Light Dependent Rxns – cont’d…ElectroChemical

Gradient…

which causes the H+ ions

to funnel through

the ATP Synthase

to form a small amountof ATP

which will then move on to the light INdependent rxns

Summing it up…Equation: E + H2O +CO2 C6H12O6 + O2

of the things in our equation…which things are input or formed in the light dependent reactions of photosynthesis?input: energy [solar] + water [roots]formed: oxygen gas

[by splitting water; goes out through stomata]

ATP SynthaseHydrogen Ions are pumped into the thylakoid

membrane after water is split…ions form electro-

chemical gradientions funnel through

ATP synthaseturns “crank”

energy from turningmakes ADP+P intoATP

Light Independent Reactionsaka Dark Reactions or Calvin Cycle

can occur in the LIGHT or the dark[light rxns can only occur when there is

sunlight]

The Calvin Cycle

Light Indep. Rxns – cont’dWhat you NEED to know:

can occur with or without light presentcomposed of the calvin cycleCarbon dioxide (CO2) is taken in and

combined with the H+ from NADPH (using ATP) to make Glucose (C6H12O6).

leftovers – ADP and NADP+ go back to light dependent reactions

Summing it up…Equation: E + H2O +CO2 C6H12O6 + O2

of the things in our equation…which things are input or formed in the light INdependent reactions of photosynthesis?input: carbon dioxide [in through stomata]formed: glucose [used by plant for food]

Overview - Photosynthesissolar

energy [photon]

ATP

NADPH

NADP+

ADP

H2O

a little bit of H2O

CO2

O2

C6H12O6

thylakoids

stroma

IMPORTANT!!Be sure to know:

what goes inwhere that came fromhow it’s used

what goes outwhere that’s goinghow it was made

HW: STUDY for closed-note quiz tomorrow or Weds on Photosynthesis & work on Cells UPA